1. Field of the Invention
This invention relates to superconducting oxide material whose electric resistance diminishes at a low temperature and a method for producing the same. The superconducting oxide material of the invention superconducts at a comparatively high temperature, e.g., the liquefying temperature of hydrogen or -253.degree. C. (20 K), and it can be produced in a reducing atmosphere.
An object of the invention is to provide a material which is suitable for electronics elements, such as SQUIDs (Superconducting Quantum Interference Devices) and superconducting transistors, superconducting wires, and the like.
2. Related Art Statement
The occurrence of phenomenon of superconductivity has been known only at a very low temperature of 4-23 K, and its application has been limited to those fields where use of such very low temperature is economically justifiable. In 1986, rare earth element-copper-oxide material was invented to make a great jump in the improvement of the transition temperature for superconductivity, and superconductivity is now available at a more readily accessible low temperature, e.g., the liquefying temperature of air.
Process which has been developed so far as the preparation of such superconducting oxide material uses a number of heat treating steps in an oxidizing atmosphere so as to introduce oxygen into the material. In producing electronics devices, thin film techniques under high vacuum is frequently used, and the need of heat treatment in the oxidizing atmosphere has been a major difficulty to be overcome before realizing the application of the superconducting oxide material to electronics. Further, in the case of superconducting wires for electric power transmission and storage, sheaths made of oxidization resisting noble metal, such as silver or platinum, have been used, and the use of costly noble metal has hampered popular application of the superconducting oxide material to power industries.